Hall Sensor Magnet Plate Alignment for Camera Mirror Positioning
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Solution Overview
Problem
In camera systems, loose shafts used for mirror mounting introduce side-to-side motion errors in position measurement due to low friction requirements, leading to inaccuracies in determining the mirror's angle, which can significantly impact control precision.
Innovation Solution
A hall sensor measures distance to a magnet on the moveable mirror support, with a magnetic metal plate attracting the magnet to maintain alignment, reducing side-to-side motion and enhancing measurement accuracy without increasing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a loose fit is used between the shaft and support to minimize friction, then the force required to move the component is reduced, but side-to-side motion occurs that introduces measurement errors
Solution Approach 1:
A magnetic plate is introduced as an intermediary element between the shaft support and the moveable component. The magnetic plate interacts with the hall sensor to provide magnetic attraction that prevents side-to-side motion of the component while allowing it to rotate freely on the loose shaft, thus eliminating measurement errors without increasing mechanical friction
Solution Approach 2:
The patent replaces mechanical constraint (tight fit between shaft and support) with a magnetic field-based constraint. Instead of using mechanical friction to prevent side-to-side motion, the system uses magnetic attraction between the hall sensor and magnetic plate to hold the component in place, allowing loose mechanical clearance while maintaining positional accuracy
2Measurement precision
If a tight fit is used between the shaft and support to prevent side-to-side motion, then measurement accuracy is improved, but friction increases requiring larger motors
Solution Approach 1:
The magnetic plate serves as an intermediary that transfers the magnetic field from the hall sensor to the moveable component. This allows the component to be held securely against side-to-side motion through magnetic attraction rather than mechanical friction, enabling accurate measurement while maintaining low friction at the shaft location
Solution Approach 2:
The patent substitutes mechanical friction-based positioning with a magnetic field-based positioning system. The hall sensor detects position through magnetic field interaction with the magnetic plate, eliminating the need for tight mechanical fits and reducing friction requirements for the motor
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution improves the accuracy of mirror position determination by minimizing side-to-side motion, allowing for precise control of the mirror's position while maintaining low friction, thus addressing the inaccuracies caused by loose shafts.
Implementation Method 1
Hall sensors are often used to measure distance and/or changes in position in applications requiring a high degree of precision with regard to the measurements
Implementation Method 2
a magnetic metal plate is placed on a side of the support in which the moveable component is mounted... the magnet which is detected by the hall sensor is attracted towards the plate thus pulling the moveable component on the shaft towards the sidewall
Data Source
AI summary
Methods and apparatus for maintaining, adjusting and/or accurately determining the position of a moveable element, e.g., a moveable shaft mounted component are described. The moveable component may be, for example, a mirror or mirror support of a camera module. A hall sensor is used to measure distance to the moveable component. To facilitate the distance measurement a magnet is secured to the moveable component. The hall sensor is used to determine the distance between the magnet and sensor. A metal plate is placed along a side of one of the supports used to support the shaft to which the moveable component is attached. The magnet which facilitates distance measurement is attracted to the plate reducing the risk of side to side movement even when the shaft fits loosely in the supports and is rotated. The magnet facilitates distance measurements and reliable control of position relative to the sidewall plate.